National Metallurgical Laboratory (NML) has come out with an eco-friendly and energy-efficient technology to extract uranium from very low-grade ore.
The bacteria in the mine water is used to extract uranium from ore containing triuranium octaoxide as low as 0.025%.
The bug extraction process, seen in the context of the country’s need for uranium in the coming years, especially in power-generation, is expected to produce an additional amount of the strategic metal.
The normal Indian uranium ore contains around 0.1% triuranium octaoxide, while Australian uranium ore, among the world’s best, contains around 0.5-0.6%.
NML sources said experiments conducted last year with the ore from Uranium Corp of India Ltd’s Turamdih mines near here on bench scale show convincing recovery of uranium from the ore with the aid of the bacteria.
The process developed in laboratory scale column has been validated by a joint NML-Ucil collaboration work on large columns of 100 kg scale with a uranium recovery of up to 70% in 60 days’ time.
“The low-uranium ore is put in heaps in different places, in such a way that the mine water containing the bug can percolate through it. The enriched solution is collected at the bottom,” said prof SP Mehrotra, director of NML.
He said it could take as much as six months to deliver the usable raw material as conditions have to be created for the organisms to multiply fast and remain active.
The process has finally been established on two-tonne columns at Ucil’s Jadugoda mine site with ‘excellent results.’
The NML director said the process was ‘very cost-effective’ as no energy consumption was involved, but there would be some expenditure on the creation of the heaps, putting the collection troughs in place at the bottom, and the percolation of the bug-containing water through the heaps.
In the normal conventional chemical processes, recovery of uranium takes place up to 50-55% levels, while the bug way recovers the metal up to 70% levels.
Support for the technology-proving plan is expected from the Atomic Energy Commission in the next phase, which will involve large-scale heaps of 200 tonne.
In the next stage, NML wants to prove the technology on commercial heaps of 15,000 tonnes that would deliver the uranium-enriched solution in a 3-6 month time frame.